1. Field of the Invention
The invention relates to a two-part piston for an internal combustion engine, comprising a piston head and a piston skirt, where the piston head features a piston crown, on the underside of which at least two boss lands, each provided with a head boss hole are connected. The piston skirt features at least two boss bodies each provided with a skirt boss hole. When assembled, the head boss holes and the skirt boss holes are flush relative to each other to accommodate a gudgeon pin.
2. The Prior Art
Generic pistons are described in U.S. Pat. No. 4,180,027 A, Great Britain Patent No. GB 140 651 A and German Patent No. DE 35 42 800 C1. Furthermore, comparable pistons are known from German Patent Nos. DE 100 49 786 A1, DE 38 32 159 C2, DE 36 02 266 A1 and European Patent No. EP 0 238 146 B1.
The common feature of the pistons described in these publications is that the piston head and the piston skirt are connected to each other merely by means of a gudgeon pin. To this end, both the piston head and the piston skirt have bosses which, when assembled, are provided with flush boss holes, through which the gudgeon pin is inserted. These types of pistons, in which the piston head and the piston skirt are joined to each other by means of the gudgeon pin, are also known as articulated-skirt pistons. The advantage of these types of pistons is that the piston head, which is subjected to greater stress by the temperatures and pressures in the adjoining combustion chamber, can be manufactured from a different material than that of the further removed piston skirt, which is subjected to less stress. For example, the piston head can be manufactured from steel and the piston skirt from an aluminum material. This approach is designed to limit damage, such as cracks and fractures, to the piston head. The disadvantage of these articulated-skirt pistons, however, is that it is comparatively awkward and complicated to assemble the piston head and piston skirt into the finished piston. In addition, a further aim of piston development is to further bring about a reduction in piston weight.